Agatha Magdalene Kim Yun-deok was born in Eunjae, Sangju, Gyeongsang-do (now, Jeoeum-ri, Ian-myeon, Sangju-gun, Gyeongbuk). When she grew up she heard about the Gospel that was being proclaimed around her hometown and accepted the faith of the Catholic religion. She moved to the Noraesan Christian Village (now, Norae 2-dong, Andeok-myeon, Cheongsong-gun, Gyeongbuk) to live with believers there.

Agatha Magdalene Kim was arrested by the police on Easter Sunday, February 22, 1815, while the Village was celebrating the Solemnity of the Resurrection of Jesus Christ. She was taken to Gyeongju with other Catholics. She had to undergo harsh interrogations and torture, however her faith in God remained firm and unshakable. The official asked her, ‘For what are you going to die after all?` She responded as follows:

"How mean and ignorant one can be, no one would deny and betray the Lord, who has created heaven and earth and all that it contains."

Agatha Magdalene Kim, who professed her faith in God bravely, was transferred to Daegu along with other fellow Catholics.

She became so weak from cruel torture and ill treatment that she betrayed her religion. The governor gave orders to set her free. The moment she stepped outside the gate of the governor`s office, she happened to meet with Andrew Kim Jong-han, who was transferred from Andong. Seeing Agatha Magdalene Kim, Andrew Kim sighed and strongly encouraged her, saying, "Please, do not miss such a good opportunity to profess your faith in God."

During that brief conversation with Andrew Kim, her faith returned and burned inside her. Stepping inside the gate of the governor`s office, she pushed away the police and with determination bravely marched toward the chief official. The surprised chief official asked her, "You just left here. What brought you back?" She answered:

"Torture was too painful to endure. So I renounced the Lord momentarily, but I realized that it was truly a great mistake. I regret and repent it, so I`m here again before you. Kill me if you want to. Now, I am a more faithful Catholic than ever."

The chief official became so furious that he ordered that the crazy woman be taken out. But Agatha Magdalene Kim came in again, and retracted her previous denial of the Catholic religion in a loud voice. The chief official grew so angry that he ordered to have her beaten harshly. Her flesh was all broken and dropped from her body, piece by piece, and her bones were broken. She fainted on the spot. She died the moment she was re-imprisoned. It was the end of April or early May 1815. Agatha Magdalene Kim was about 50 years old.